Mycobacterium gordonae-induced humidifier lung.

Background: Nontuberculous mycobacteria are well known to be a cause of hot tub lung, however, to our knowledge, there exists no case report of humidifier lung induced by mycobacteria.

Case Presentation: A case of a nonimmunocompromised female patient with Mycobacterium gordonae-induced humidifier lung is described. She spontaneously recovered after discontinuing ultrasonic humidifier use. When subjected to a provocation test, she demonstrated acute respiratory distress with signs and symptoms, consistent with hypersensitivity pneumonitis. Before and after the provocation test, water in the humidifier reservoir revealed only Mycobacterium gordonae by the microbiologic analyses.

Conclusion: To our knowledge, this is the first report of humidifier lung induced by nontuberculous mycobacteria. Although nontuberculous mycobacteria are well-known to be agents of hot tub lung or metal working fluid lung, physicians should also consider the pathogen as a cause of hypersensitivity lung reaction associated with humidifier use.